The present invention relates to a developer discharge method for a developing device which develops an electrostatic latent image which is formed on an image bearing member by using a developer which includes toner and a carrier, and the developing device.
Since the developer deteriorates with use in the developing device, a constitution is proposed, in which only the developer is replaced while the developing device is not replaced, by discharging the deteriorated developer in the developing device and supplying a new developer (For example, Japanese Laid-Open Patent Application (JP-A) 2018-63283). In a case of a constitution described in JP-A 2018-63283, a first chamber for supplying the developer to a developing sleeve and a second chamber which forms a circulation passage of the developer with the first chamber are arranged vertically. Thus, in a way of conveying the developer by conveying screws which are arranged in the first chamber and the second chamber respectively, it is possible to move the developer to the second chamber by gravity and further collect the developer in a collecting container which is connected to the second chamber.
In recent years, from a perspective of a resource reutilization and an environmental protection, it is required to reuse a used developing device. Here, in a case of collecting the used developing device, unlike at a time of shipment, it may be transported without sealing the developer, so the developer may scatter during transportation when a large amount of developer is accommodated in the used developing device. As a result, in a case of reuse of the developing device, a cleaning work becomes more complicated and a reproduction cost may be increased.
Consequently, as a constitution which is described in JP-A 2018-63283, it is conceivable that the developer is discharged by driving the conveying screw before transporting the used developing device. In the case of the constitution described in JP-A 2018-63283, the first chamber and the second chamber are arranged vertically, so it is easy to discharge the developer by gravity.
On the other hand, as a developing device, there is a constitution in which the first chamber and the second chamber are arranged adjacent to each other in a horizontal direction or a diagonal direction, however, it is impossible to properly discharge the developer by simply driving the conveying screw in such a constitution. That is, in a case that a first conveying member which conveys the developer in the first chamber and a second conveying member which conveys the developer in the second chamber are constituted to be overlapped at least a part of them when viewed from a horizontal direction, it is impossible to discharge a sufficient amount of the developer by simply driving the first conveying member and the second conveying member.
In response to such situation, an object of the present invention is to discharge the developer from the used developing device.
Another object of the present invention is providing a developer discharging method of a developing device including, a developer carrying member constituted to carry and convey a developer, containing toner and a carrier, to a developing position, a developer container including a first chamber constituted to accommodate the developer to be supplied to the developer carrying member, and a second chamber partitioned from the first chamber by a partition wall, the developer being circulated between the first chamber and the second chamber, a first communication portion constituted to permit the developer to communicate from the first chamber to the second chamber, a second communication portion constituted to permit the developer to communicate from the second chamber to the first chamber, a first conveying screw provided in the first chamber and constituted to convey the developer with respect to a first direction from the second communication portion toward the first communication portion, a second conveying screw provided in the second chamber and constituted to convey the developer with respect to a second direction from the first communication portion toward the second communication portion, and a developer discharging portion provided in a passage continuous with the first chamber of an upstream side of the second communication portion with respect to the first direction and constituted to discharge the developer from the developing device, the developer discharging method comprising an inserting step for inserting a shield member into the second communication portion via an inserting opening of the developer container, the shield member causing the second communication portion from an opening state for opening the second communication portion to a shielding state for shielding the second communication portion and a discharging step, by rotatably driving the first conveying screw in a direction opposite to a direction of rotatably driving the first conveying screw during a developing operation of developing an electrostatic image formed on an image bearing member in a state in which the shielding member is inserted into the second communication portion in the inserting step, and by rotatably driving the second conveying screw in a direction opposite to a direction of rotatably driving the second conveying screw during the developing operation in the state in which the shielding member is inserted into the second communication portion in the inserting step, for discharging the developer from the developing device via the developer discharging portion.
Another object of the present invention is providing a developer discharging method of a developing device including, a developer carrying member constituted to carry and convey a developer, containing toner and a carrier, to a developing position, a developer container including a first chamber constituted to accommodate the developer to be supplied to the developer carrying member, and a second chamber partitioned from the first chamber by a partition wall, the developer being circulated between the first chamber and the second chamber, a first communication portion constituted to permit the developer to communicate from the first chamber to the second chamber, a second communication portion constituted to permit the developer to communicate from the second chamber to the first chamber, a first conveying screw provided in the first chamber and constituted to convey the developer with respect to a first direction from the second communication portion toward the first communication portion, a second conveying screw provided in the second chamber and constituted to convey the developer with respect to a second direction from the first communication portion toward the second communication portion, and a developer discharging portion provided in a passage continuous with the second chamber of an upstream side of the first communication portion with respect to the second direction and constituted to discharge the developer from the developing device, the developer discharging method comprising an inserting step for inserting a shield member into the first communication portion via an inserting opening of the developer container, the shield member causing the first communication portion from an opening state for opening the first communication portion to a shielding state for shielding the first communication portion and a discharging step, by rotatably driving the first conveying screw in a direction opposite to a direction of rotatably driving the first conveying screw during a developing operation of developing an electrostatic image formed on an image bearing member in a state in which the shielding member is inserted into the first communication portion in the inserting step, and by rotatably driving the second conveying screw in a direction opposite to a direction of rotatably driving the second conveying screw during the developing operation in the state in which the shielding member is inserted into the first communication portion in the inserting step, for discharging the developer from the developing device via the developer discharging portion.
Another object of the present invention is providing a developing device comprising a developer carrying member constituted to carry and convey a developer, containing toner and a carrier, to a developing position, a developer container including a first chamber constituted to accommodate the developer to be supplied to the developer carrying member, and a second chamber partitioned from the first chamber by a partition wall, the developer being circulated between the first chamber and the second chamber, a first communication portion constituted to permit the developer to communicate from the first chamber to the second chamber, a second communication portion constituted to permit the developer to communicate from the second chamber to the first chamber, a first conveying screw provided in the first chamber and constituted to convey the developer with respect to a first direction from the second communication portion toward the first communication portion, a second conveying screw provided in the second chamber and constituted to convey the developer with respect to a second direction from the first communication portion toward the second communication portion and a developer discharging portion provided in a passage continuous with the first chamber of an upstream side of the second communication portion with respect to the first direction and constituted to discharge the developer from the developing device, wherein the developer container is provided with an inserting opening into which a shield member is to be inserted, the shield member causing the second communication portion from an opening state for opening the second communication portion to a shielding state for shielding the second communication portion.
Another object of the present invention is providing a developing device comprising a developer carrying member constituted to carry and convey a developer, containing toner and a carrier, to a developing position, a developer container including a first chamber constituted to accommodate the developer to be supplied to the developer carrying member, and a second chamber partitioned from the first chamber by a partition wall, the developer being circulated between the first chamber and the second chamber, a first communication portion constituted to permit the developer to communicate from the first chamber to the second chamber, a second communication portion constituted to permit the developer to communicate from the second chamber to the first chamber, a first conveying screw provided in the first chamber and constituted to convey the developer with respect to a first direction from the second communication portion toward the first communication portion, a second conveying screw provided in the second chamber and constituted to convey the developer with respect to a second direction from the first communication portion toward the second communication portion and a developer discharging portion provided in a passage continuous with the second chamber of an upstream side of the first communication portion with respect to the second direction and constituted to discharge the developer from the developing device, wherein the developer container is provided with an inserting opening into which a shield member is to be inserted, the shielding member causing the first communication portion from an opening state for opening the first communication portion to a shielding state for shielding the first communication portion.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Part (a) of
A first embodiment will be described by using
[Image Forming Apparatus]
Four photosensitive drums 101a, 101b, 101c, and 101d are cylindrical photosensitive members respectively which are rotated and driven respectively in a clockwise direction in
The electrostatic latent image which is formed on each photosensitive drum from 101a to 101d is developed by a developer in each developing device 200a, 200b, 200c, and 200d. That is, each of the developing devices from 200a to 200d attaches a toner charged with a same polarity as each of the photosensitive drums from 101a to 101d and visualizes the electrostatic latent image as yellow, magenta, cyan, and black toner image (reverse developing).
Each of the toner images which are developed on the photosensitive drums from 101a to 101d is primarily transferred to an intermediary transfer belt 106 as an intermediary transfer member which is rotated and driven in a counterclockwise direction in
On the other hand, a recording material P such as paper, fed from any of a cassette 111, a cassette 112 or a manual feed tray 113 which accommodate recording materials, is fed to a registration roller 116 by a feeding roller 114 or a conveying roller 116. And, after a leading end of the recording material P urges the stopped registration roller 116 and forms a loop, the registration roller 116 starts rotating in synchronization with the toner image on the intermediary transfer belt 106. And the recording material P is fed to a secondary transfer portion where an outer secondary transfer roller 108 urges the intermediary transfer belt 106. Incidentally, as a recording material, a sheet such as a paper and a plastic sheet is included.
The toner image on the intermediary transfer belt 106 is secondarily transferred to the recording material P by the outer secondary transfer roller 108 in the secondary transfer portion. At this time, a secondary transfer voltage (secondary transfer bias), which is a voltage of opposite polarity to a toner charge polarity at a time of development, is applied to the outer secondary transfer roller 108. Then, the toner image, which is transferred to the recording material P, is fixed to the recording material P by heat and pressure of a fixing device 109, and is discharged from a discharging portion 110a or a discharging portion 110b to an outside of the apparatus. Further, a transfer residual toner on the intermediary transfer belt 106, which is not transferred and remains in the secondary transfer portion, is removed and collected by an intermediary transfer belt cleaner 117.
Incidentally, the image forming apparatus 100 includes an operation portion 120 which is possible to operate the image forming apparatus 100, such as starting and stopping an image forming operation of the image forming apparatus 100 and various settings. The operation portion 120 is possible to display various information of the image forming apparatus 100. In the embodiment, the operation portion 120 includes a touch panel 121 as a display portion, displays information on the touch panel 121, and furthermore is possible to operate various settings and operation of the apparatus by touch operation.
[Developing Device]
Next, developing devices from 200a through 200d of the embodiment will be described by using
The developing device 200a of the embodiment utilizes a two-component developing method which uses toner (nonmagnetic) and a carrier (magnetic) as a developer. The two-component developing method includes advantages such as a stability of an image quality and a durability of an apparatus, compared to other developing methods which are currently proposed. The developing device 200a accommodates the two-component developer in the developer container 201, and an amount of the developer is approximately 250 g in the embodiment. Further, a mixing ratio of toner and carrier is approximately 1:9 by weight. However, the amount of developer and the mixing ratio of toner and carrier should be adjusted appropriately depending on a constitution of the developing device 200a, a charge amount of the toner, a particle diameter of the carrier, and a constitution of the image forming apparatus 100, and should not be limited to the number.
As shown in
The developing sleeve 203 is formed with nonmagnetic material, and while the developing sleeve 203 rotates during a developing operation, a two-component developer inside the developer container 201 is carried in a layered form and is conveyed in a direction toward a developer regulating member (blade for example) 204. During the developing operation is during an operation (hereafter also referred as “during circulating conveyance”) when the developing sleeve 203, a conveying screw 205, and a mixing screw 206 described below are rotated in a forward direction (first direction) and the developer is circulated. The developer regulating member 204 is arranged opposing a surface of the developing sleeve 203 by a predetermined gap. The developer, which is carried by the developing sleeve 203, is regulated in quantity by the developer regulating member 204 and becomes a layer of a predetermined thickness, and then conveyed to the developing area. And the developer is supplied to the photosensitive drum 101a in the developing area, and an electrostatic latent image which is formed on the photosensitive drum 10 is developed. After developing the electrostatic latent image, the developer enters inside the developer container 201 according to a rotation of the developing sleeve 203, is removed from a surface of the developing sleeve 203 at a scraping position and is collected into the developer container 201.
A space inside the developer container 201 is divided into two parts by a partition wall 207, which are a developing chamber 215 as a first chamber which is possible to accommodate the developing sleeve 203 and the developer, and a mixing chamber 216 as a second chamber which is possible to accommodate the developer. That is, the developing chamber 215 accommodates the developer to supply to the developing sleeve 203. The mixing chamber 216 forms a circulating passage of the developer between the mixing chamber 216 and the developing chamber 215. The partition wall 207 divides into the developing chamber 215 and the mixing chamber 216. In the embodiment, the developing chamber 215 and the mixing chamber 216 are arranged in a substantially horizontal direction adjacent to each other, and the partition wall 207 is arranged between them in a substantially vertical direction.
In the developing chamber 215, a conveying screw 205 is arranged as a first conveying member, and in the mixing chamber 216, the mixing screw 206 is arranged as a second conveying member. The developer in the developing chamber 215 (first chamber) is conveyed by the conveying screw 205 in a direction of an arrow A in
Here,
As shown in
The first opening portion 207a and the second opening portion 207b form a circulating passage which circulates the developer by connecting the developing chamber 215 with the mixing chamber 216. The conveying screw 205 and the mixing screw 206 mix the developer in the developer container 201, and convey and circulate the developer in the developer container 201. Specifically, the first opening portion 207a is an opening portion to deliver the developer from the developing chamber 215 to the mixing chamber 216 during developing operation (during a rotation of the conveying screw 205 and the mixing screw 206 in a forward direction, as will be described below). The second opening portion 207b is formed in a downstream side of the developer conveying direction of the mixing screw 206 than the first opening portion 207a and is an opening portion to deliver the developer from the mixing chamber 216 to the developing chamber 215 during developing operation.
The developing sleeve 203, the conveying screw 205, and the mixing screw 206 described above are driven by a motor 230 which is capable of forward and reverse rotation as a driving source (developing drive means). Specifically, the motor 230 is provided in a side of the main assembly 100A of the image forming apparatus 100, and when the developing device 200a is mounted on the main assembly 100A, the motor 230 is connected to, for example, an end portion of the conveying screw 205 in a side of the developing device 200a via a coupling. And by driving the motor 230, the developing sleeve 203, the conveying screw 205 and the mixing screw 206 are rotationally driven. That is, a coupling which is connected to the motor 230 is provided at one end portion with respect to a direction of a rotational axis of the conveying screw 205, and a gear train for a driving transmission to the mixing screw 206 and the developing sleeve 203 at the other end portion. And a driving force of the motor 230 is input to one end portion of the conveying screw 205, and the driving force is transmitted to the developing sleeve 203 and the mixing screw 206 via the conveying screw 205 and the gear train. However, the constitution of the driving transmission is not limited to this, and it may be constituted that the driving force is input from the motor 230 to the developing sleeve 203 and the mixing screw 206, for example. In any case, the motor 230 is possible to drive the developing sleeve 203, the conveying screw 205, and the mixing screw 206.
The motor 230 and the developing device 200a are controlled by a control portion 240. The control portion 240 also controls an entire image forming apparatus 100 and includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU controls each of portions, while reading a program corresponding to a control procedure which is stored in the ROM. Further, the RAM stores working data and input data, and the CPU controls by referring to data stored in the RAM based on the program described above, etc.
In the developing device 200a which is constituted as described above, the developer is provided from the developing chamber 215 to the developing sleeve 203, and the developer, after developing the electrostatic latent image on the photosensitive drum 101a, is collected in the developing chamber 215. And the developer is mixed by circulating conveyance of the developer between the developing chamber 215 and the mixing chamber 216, and the developer is provided from the developing chamber 215 to the developing sleeve 203 again.
[Constitution of Discharging Developer]
In the developing device, in a case that the same developer is continuously mixed over a long period of time, the developer deteriorates. For this reason, the developer is regularly replaced in a case that the image forming apparatus is used for a long period of time. In this case, from a viewpoint of a resource recycling and an environmental protection, it is required to reuse the used developing device.
In a case of reusing the used developing device, the used developing device is dismounted from the image forming apparatus and packed with a packing material for transportation, however, it is desirable to remove a sufficient amount of the developer (for example, approximately 75% in volume) which is still accommodated in the developer container before the transportation. This is because, when the used developing device, in which the developer is still accommodated, arrives at a recycling factory, the developer may be spilled in the packaging material during transportation and the used developing device may be covered in the developer. Further, it is easier to leak the developer in a case that the packaging material itself, which encloses the used developing device, is transported in an upside down state.
In a case that the used developing device is covered in the developer, when the used developing device is reused, cleaning workload, such as using a vacuum cleaner to suck up a large amount of the developer which is adhered to the used developing device, is enormous at the recycling factory and this leads to increase a cost of a reused product. Thus, in the embodiment, it is constituted that it is possible to discharge the developer from the used developing device.
As shown in
During a developing operation such as image forming, the developer, which flows from the mixing chamber 216 to the developing chamber 215 via the second opening portion 207b, is conveyed in the direction of the arrow A by the conveying blade portion 2051 of the conveying screw 205. This prevents the developer from flowing into the discharging passage 213 and being discharged from the discharging port 208. Thus, it is not enough to discharge the developer from the discharging port 208 by simply rotationally driving the conveying screw 205. Therefore, constitutions as will be described below is adopted in the embodiment.
[Shielding Member]
The developer 200a in the embodiment is constituted to be capable of switching by a shielding member 211, between an opening state that the developer is able to pass through the second opening portion 207b which is an opening portion in a side near the discharging port 208 and a shielded state that the developer is shielded to pass through the second opening portion 207b. This point will be described by using
The shielding member 211 is a sheet shaped member, such as a plastic sheet. When the developing device 200a is in use, such the shielding member 211 is not inserted into the insertion opening 210a, and in a case of replacing the developing device 200a due to deterioration of the developer or other reasons, as shown in
In the embodiment, the insertion opening 210a is formed so that the shielding member 211 is positioned in an upstream side of the flow direction of the developer which is passing through the second opening portion 207b with respect to the partition wall 207. Then, in a case that the shielding member 211 is inserted into the insertion opening 210a, the shielding member 211 is arranged along the surface of the side of the developing chamber 215 of the partition wall 207. With this constitution, it is possible to block the flow of the developer which is passing through the second opening portion 207b by the shielding member 211 without a need for a complicated constitution.
Incidentally, inside the developing top cover 210, a sealing member 210b which is constituted with a flexible form such as a rubber so as to cover the insertion opening 210a. The sealing member 210b is provided with a cutout along the insertion opening 210a and a gap between the shielding member 211 and the insertion opening 210a is sealed while the shielding member 211 is inserted. In this way, it is possible to suppress a leakage of the residual developer from between the shielding member 211 and the insertion opening 210a during a transportation of the used developing device 200a.
[Developer Discharging Mode]
Next a developer discharging mode, in which the developer is discharged from the used developing device by using the constitution described above, will be described. First, the control portion 240 of the image forming apparatus 100 is capable of performing an image forming mode which conducts a normal developing operation as a first mode and a developer discharging mode as a second mode. In the image forming mode, the conveying screw 205 and the mixing screw 206 are driven in a forward direction in an open state in which the second opening portion 207b is not shielded by the shielding member 211. In the developer discharging mode, the conveying screw 205 and the mixing screw 206 are driven in a backward direction (second direction) which is an opposite direction to the forward direction, while in a shielded state in which the second opening portion 207b is shielded by the shielding member 211. Incidentally, as described above, the motor 230, which drives the conveying screw 205 and the mixing screw 206, also drives the developing sleeve 203, so the motor 230 drives the developing sleeve 203 in the image forming mode and the developer discharging mode.
That is, in the developer discharging mode, after the second opening portion 207b is shielded by the shielding member 211, the motor 230 drives the developing sleeve 203, the conveying screw 205, and the mixing screw 206 in an opposite direction to a time of circulating conveyance (time of image forming). In this case, driving speeds of the developing sleeve 203, the conveying screw 205, and the mixing screw 206 in the developer discharging mode are the same as those of the developing sleeve 203, the conveying screw 205, and the mixing screw 206 in the image forming mode. A time for executing the developer discharging mode is set as a predetermined time (for example 180 seconds). That is, when a predetermined time is passed after the developer discharge mode is started, the drive of the developer sleeve 203, the conveying screw 205 and the mixing screw 206 is stopped.
In this way, the developer in the mixing chamber 216 is conveyed in an opposite direction to the direction of the arrow B in
The developer, which is flowed into the discharging passage 213, is discharged from the discharging port 208, and as shown in
Incidentally, in the description above, the driving speeds of the developing sleeve 203, the conveying screw 205, and the mixing screw 206 are set to be the same in the developer discharging mode and the image forming mode. However, the control portion 240 may control the driving speeds of the developing sleeve 203, the conveying screw 205, and the mixing screw 206 in the developer discharging mode as will be described below. That is, during a first period from a start of the developer discharging mode (start of driving of the motor 230 in the reverse direction), the driving speeds of the developing sleeve 203, the conveying screw 205, and the mixing screw 206 are set to be slower than in the image forming mode. And during a second period following the first period, the driving speed are set to be the same as in the image forming mode.
First, during an execution of the developer discharging mode, the mixing screw 206 may lock due to a heavy load when trying to rotate the mixing screw 206 in such a state, since an amount of the developer in the mixing chamber 216 is large. Therefore, in the developer discharging mode, during the first period, by driving the conveying screw 205 and the mixing screw 206 slowly, the developer is discharged from the discharging port 208. And, at a time when the amount of the developer in the mixing chamber 216 is decreased to some extent, that is, at a time when a risk of screw lock is eliminated, the second period begins and the screw speed is set to be the same as at a time of image forming. In this way, it is possible to discharge the developer from the discharging port 208 promptly.
[First Example of Developer Discharging Mode Flow]
Here, a first example of a developer discharging mode flow described above will be described by using
Specifically, as shown in
Then, for example, a screen, which is shown in
Incidentally, before executing the developer discharging mode described above, the shielding member 211 is inserted into the developing device in which the operator would like to execute the developer discharging mode. A timing for inserting the shielding member 211 may be any time before executing the developer discharging mode. For example, the timing of inserting the shielding member 211 is before or after shifting to the service mode, when the button for executing the developer discharging mode is pushed, when the developing device which the operator would like to execute the developer discharging mode is selected, etc. Further, for example, when the operator selects the developing device which the operator would like to execute the developer discharging mode, the touch panel 121 displays that the shielding member 211 is to be inserted into the selected developing device. And after inserting the shielding member 211, the developer discharging mode may be executed by mounting the developing device on the main assembly 100A. Further, in this case, the developer discharging mode may be executed by displaying a confirmation button and pushing the confirmation button.
[Second Example of the Developer Discharging Mode Flow]
Next, a second example of a developer discharging mode flow described above will be described by using
Specifically, as shown in
Incidentally, in the example as well, in a case that it is determined that the developing device reaches the end of the lifetime (YES in S11), a screen as shown in
In this way, in the embodiment, by driving the conveying screw 205 and the mixing screw 206 reversely while the second opening portion 207b near the discharging port 208 is shielded by the shielding member 211, the developer in the developer container 201 is discharged from the discharging port 208. Thus, even in a constitution that the conveying screw 205 and the mixing screw 206 are arranged so that they overlap at least partially when viewed horizontally, it is possible to discharge the developer properly.
That is, even in the developing device 200a in which the developing chamber 215 and the mixing chamber 216, where the developer is circulated, are arranged in a substantially horizontal direction, it is possible to discharge the developer by shielding the second opening portion 207b which is the one closer to the discharging port 208 of two opening portions which are provided in both ends of the partition wall 207. In this way, it is possible to suppress a scattering of the developer due to transportation for collecting the developing device and reduce a cleaning cost for recycling.
Incidentally, during the execution of the developer discharging mode, when the developing sleeve 203, which carries the developer on its outer peripheral surface, is rotated in an opposite direction to a time of an image forming, the developer may be adhered to an outside surface of a leading end of the developer regulating member 204. In this case, after completion of discharging the developer in the developer container 201 (during a certain period at an end of the developer discharging mode), the developing sleeve 203 may be rotated about half to one revolution by driving the motor 230 in a same direction (forward direction) as a time of an image forming. Thus, the developer, which is adhered to the outside surface of the leading end of the developer regulating member 204, is possible to be carried on a surface of the developing sleeve 203 again by a magnetic force of the magnet 202 inside the developing sleeve 203, and to be collected into the developer container 201.
A second embodiment will be described by using
Even when the developer discharging mode is executed and the developer discharging is completed, a small amount of the developer may remain in a vicinity of the returning blade portion 2062 of the mixing screw 206. Thus, it is desirable that the shielding member 211a remains inserted into the insertion opening 210a, in order to prevent from dispersing the residual developer to an outside of the developing device 200a passing through the second opening portion 207b, when the developing device 200a is collected. Further, by a vibration of the collected developing device 200a during a transportation, etc., the shielding member 211a may fall off unintentionally.
Therefore, in the embodiment, as shown in
The returning shapes 211b are formed so as to protrude toward each outside with respect to a width direction at both ends of the shielding member 211a with respect to the width direction, and further, each end portion of a downstream side with respect to an insertion direction is formed to be an inclined surface which is inclined to an inside with respect to the width direction as it comes to a downstream side. Further, an upstream end of the returning shape 211b with respect to the insertion direction is designed to be a straight line shape which is substantially parallel to the inside surface of the developing top cover 210. In this way, when the shielding member 211a is inserted into the insertion opening 210a, the inclined surface of the returning shape 211b serves as a guide, the returning shape 211b is elastically deformed, and the shielding member 211a is inserted into the insertion opening 210a. And, after insertion, the returning shape 211b is elastically restored, the straight line shape portion is locked in the inside surface of the developing top cover 210, and then, the shielding member 211a is prevented from slipping off from the insertion opening 210a.
In a case of such the embodiment, since the shielding member 211a is prevented from slipping off after inserting into the insertion opening 210a, it is possible to further suppress a leakage of the developer during a transportation of the used developing device, etc.
A third embodiment will be described by using
At a time of an initial shipment of the developing device 200a, there is a constitution in which a part of a space in the developer container 201 is sealed with sheet material, etc. and an initial developer is enclosed at a high filling rate. In such the constitution, in a case that the insertion opening 210a is constituted of a part of a sealed space, the sealing member 210b with the cutout described above is not enough to seal. In such cases, an insertion opening cover member may be provided separately to cover the insertion opening 210a. However, in a case that an insertion opening cover is provided separately, a number of parts may increase.
Therefore, in the embodiment, as shown in
With such the constitution, at the time of the initial shipment of the developing device 200a, the shielding member 211c covers the insertion opening 210a, so it is possible to suppress an initial leakage of the developer from the insertion opening 210a. On the other hand, at the time of replacing the used developing device 200a, by removing the shielding member 211c and inserting into the insertion opening 210a, it is possible to shield the second opening portion 207b and execute the developer discharging mode as described above.
Incidentally, the insertion opening 210a may be exposed by providing a perforation and cutting it out, and the shielding member 211c, which is cut out, may be inserted into the insertion opening 210a. Further, the shielding member may also be a shielding member whose shape is like the second embodiment.
The fourth embodiment will be described by using parts (a) and (b) of
First, in a case of a constitution of the first example in the embodiment shown in part (a) of
In the example, in the second opening portion 207b, which is closer to the discharging port 208, the developer flows into the mixing chamber 216 from the developing chamber 215 by receiving an effect of gravity as well. However, by shielding the second opening portion 207b during the developer discharging mode, it is possible to block an inflow of the developer from the developing chamber 215 to the mixing chamber 216 and to discharge the developer. Incidentally, the same applies to a constitution in which the conveying screw 205 and the mixing screw 206 are arranged in parallel, a top of an outer diameter of the conveying screw 205 is higher than a top of an outer diameter of the mixing screw 206, and, furthermore, a position of a bottom of the developing chamber 215 is higher than a position of a bottom of the mixing chamber 216.
Next, in a case of a constitution of the second example in the embodiment as shown in part (b) of
In this example, even though the developing chamber 215 is lower than the mixing chamber 216 as described above, when a lower end 2071b of the second opening portion 207b which is closer to the discharging port 208 is positioned below an upper end of the outer diameter of the conveying screw 205, the developer flows into the mixing chamber 216 from the developing chamber 215 in the second opening portion 207b. However, in a case of such an example, by shielding the second opening portion 207b during the developer discharging mode, it is also possible to block the inflow of the developer from the developing chamber 215 to the mixing chamber 216 and to discharge the developer. Incidentally, the same applies to the constitution in which the conveying screw 205 and the mixing screw 206 are arranged in parallel, the top of the outer diameter of the conveying screw 205 is lower than the top of the outer diameter of the mixing screw 206, and, furthermore, the position of the bottom of the developing chamber 215 is lower than a position of a bottom of the mixing chamber 216.
A fifth embodiment will be described with reference to each of the figures described above. In the embodiment, the discharging port 208 is arranged in an upstream side with respect to the developer conveying direction of the mixing screw 206 in the mixing chamber 216 during the developing operation. Since other constitutions and actions are the same as those of the first embodiment described above, the same reference numerals are attached to the same constitutions, and descriptions and illustrations for the same constitutions are omitted or simplified, and points which differ from the first embodiment will be mainly described below.
In the embodiment, as described above, the discharging port 208 is arranged in the upstream side of the first opening portion 207a of the mixing chamber 216. In a case of this constitution, when executing the developer discharging mode, the first opening portion 207a, which is closer to the discharging port 208, is shielded by the shielding member 211. That is, in a case of the embodiment, an opening portion, which is able to switch between an opened state and a shielded state by the shielding member 211, is the first opening portion 207a. Thus, the insertion opening 210a of the shielding member 211 is arranged in a substantially upper position of the first opening portion 207a.
Further, the insertion port 210a is formed so that the shielding member 211 is positioned in an upstream side of the partition wall 207 with respect to a direction of a flow of the developer passing through the first opening portion 207a. And, when the shielding member 211 is inserted into the insertion opening 210a, it is arranged so that the shielding member 211 is aligned along a surface of the mixing chamber 216 side of the partition wall 207. In this way, without any needs of complex constitutions, it is possible to shield the flow of the developer, which is passing through the first opening portion 207a, by the shielding member 211. Incidentally, in the embodiment, it is possible to apply to the constitution of each of the embodiments described above.
A sixth embodiment will be described by using
In the first embodiment described above, as shown in
On the other hand, in the embodiment, as shown in
The angles of the conveying surfaces 2051a and 2051b, on both sides of the conveying blade portion 2051 of the conveying screw 205A, may be set appropriately to be desired developer conveying properties according to constitutions of the developing devices during each of the circulating and conveying time and the developer discharging time.
A seventh embodiment will be described by using
In a case of the constitution of the first embodiment described above, during the developer discharging mode, the motor 230 drives the developing sleeve 203, the conveying screw 205, and the mixing screw 206 in an opposite direction to a direction during circulating and conveying the developer (during the image forming mode). On the other hand, in the image forming apparatus in which the photosensitive drum 101a forms images by rotating at a plurality of speeds, a speed ratio of the conveying screw 205 and the mixing screw 206 against the developing sleeve 203 is designed to be switchable. Specifically, as shown in
In the constitution, it is possible for the developing sleeve 203 to be driven by the second motor 2302 in a same direction with a direction during circulating and conveying the developer, while during the developer discharging mode, the conveying screw 205 and the mixing screw 206 are driven by the first motor 2301 in an opposite direction to a direction during circulating and conveying the developer. Even in this case, the developer, which is retained on the surface of the developing sleeve 203, is separated at a separating position as the developing sleeve 203 rotates, and is collected in the developing chamber 215. Along with this, as an amount of the developer in the developing chamber 215 decreases, a new developer is not lifted up to the surface of the developing sleeve 203 and its surface becomes a state that the developer is separated.
An eighth embodiment will be described by using
[Developer Automatic Replacement Method]
In the developing device of the two-component developing method, deterioration of the developer, especially deterioration of the carrier, due to a long term continuous use is inevitable, so some constitutions apply the developer automatic replacement method which aims to extend a lifetime of the developing device. The constitution will be described by using
In the developer automatic replacement method, in addition to the toner which consumed by a developing operation of the developing device 200A, a supply developer which includes a small amount of the carrier is supplied to the developing device 200A from a developer supplying portion 119, as well as an excess developer in the developing device 200A is discharged to an external collecting container 118. In the embodiment, the carrier which is included in the supply developer is approximately 10% by a weight ratio. However, a mixing ratio of the carrier should be appropriately adjusted according to a constitution of the developing device 200A, an ease of a deterioration of the developer, a constitution of the image forming apparatus, etc., and it is not necessarily limited to the value.
Since the excess developer is discharged almost simultaneously with supply of the supply developer by the developer automatic replacement method, it is possible to stabilize overall properties of the developer over a long period of time without increasing a size of the image forming apparatus and driving up a cost. Further, since the developer is automatically replaced as an image is formed, it is possible to decrease a frequency of works such as a replacement of the developer and a replacement of the developing device and it contributes a decrease of an operating cost.
As shown in
As shown in
As shown in
On the other hand, when an amount of the developer in the developer container 201 increases by a repeated supply of the supply developer, since the pitch of the retention blade portion 2053 of the conveying screw 205B is small and the conveying force is small as described above, a rate of conveying the developer in the direction of the arrow A does not match an amount of the developer flowing from the mixing chamber 216 into the developing chamber 215. As a result, a surface height of the developer retained in a vicinity of the second opening portion 207b rises, and an excess developer climbs over the retention blade portion 2053 and enters the discharging passage 213 as indicated by a dashed arrow. And the excess developer is conveyed to the discharging port 208 by the discharging blade portion 2054 in the discharging passage 213. The developer, which is discharged from the discharging port 208, is collected and stored in the collecting container 118.
As described above, in the developer automatic replacement method, the developer is replaced automatically and gradually, by keeping a constant amount of the developer in the developer container 201 while the carrier is supplied as a supply developer with the toner and the excess developer is discharged.
[Developer Discharging Mode Using Discharging Port for Developer Automatic Replacement]
As described above, even in the developing device 200A which adopts the developer automatic replacement method, the developer may be replaced due to reasons such as deterioration of the developer or durability deterioration of other components. In such a case, a procedure how to discharge the developer by using the discharging port 208 for the developer automatic replacement without providing a new discharging port for discharging the developer and an operation of the developing device 200A will be described below.
Similar to the first embodiment, the insertion opening 210a and the sealing member 210b are provided in the developing top cover 210, and it is possible to shield the second opening portion 207b, which is closer to the discharging port 208, by the shielding member 211.
Thus, the developer in the mixing chamber 216 is conveyed in an opposite direction to an arrow B by the mixing screw 206 and is flowed into the developing chamber 215 from the mixing chamber 216 via the first opening portion 207a. On the other hand, the developer in the developing chamber 215 is conveyed in an opposite direction to a direction of an arrow A, however, since the second opening portion 207b is shielded by the shielding member 211 and a circulation of the developer to the mixing chamber 216 is blocked, the developer is conveyed to the discharging passage 213 by the conveying blade portion 2051 and the retention blade portion 2053 of the conveying screw 205B. In the discharging passage 213, the developer receives a conveying force by the discharging blade portion 2054 in a direction of an arrow A, however, as described above, the outer diameter of the discharging blade portion 2054 is small and the conveying force is also small, so the developer is discharged from the discharging port 208 against this and collected and stored in the collecting container.
Incidentally, in the embodiment, as shown in
Further, similar to the first embodiment, in a case that the developing sleeve 203 is also rotated during the developer discharging mode, the developer, which is retained on the surface of the developing sleeve 203, is also separated and is collected in the developing chamber 215, and the surface of the developing sleeve 203 is possible to become a state that it is separated from the developer. In this time, the developing sleeve 203 may be rotationally driven in an opposite direction to a direction during the developing operation together with the conveying screw 205B and the mixing screw 206, and as described above, the developing sleeve 203 may be rotationally driven by the second motor 2302 in a same direction as a direction during the developing operation.
As described above, even in the developing device 200A which adopts the developer automatic replacement method, it is possible to discharge the developer by using the discharging port 208 for the developer automatic replacement. That is, even in the embodiment, during an execution of the developer discharging mode, it is sufficiently possible to discharge the developer in the developing container 201 by shielding the second opening portion 207b which is closer to the discharging port with the shielding member 211.
Incidentally, in the developing device 200A described above, an example, in which the developer supplying port 217 is arranged in an upstream side of the mixing screw 206 in the mixing chamber 216 with respect to the developer conveying direction, is shown. However, the developer supplying port may be arranged at a position after the developer, which is collected in the developer container 201 from the developer sleeve 203 accompanied with a rotation of the developing sleeve 203 after developing an electrostatic latent image, is merged into the circulating passage, for example, at a position of a downstream side of the developing chamber 215 with respect to the developer conveying direction. In this case, the supply developer is conveyed to the circulating passage in the developer container 201 by the returning blade portion 2052.
Further, in the embodiment, in the conveying screw 205B shown in
In such a constitution, during circulating and conveying of the developer, a part of the developer which is flowed from the mixing chamber 216 is conveyed in an opposite direction to the direction of the arrow A by the first retention blade portion 2053a, however, the developer is pushed back by the second retention blade portion 2053b and is prevented from flowing into the discharging passage 213. However, as an amount of the developer increases, the excess developer climbs over the second retention blade portion 2053b, and is flowed and discharged into the discharging passage 213.
On the other hand, during the developer discharging mode, by driving the conveying screw 205C in a backward direction, the developer, which is conveyed in an opposite direction to the direction of the arrow A by the conveying blade portion 2051, is pushed back by the first retention blade portion 2053a and retained. However, since the second opening portion 207b is shielded by the shielding member 211 and a circulation of the developer into the mixing chamber 216 is blocked, a surface height of the developer rises. And the developer climbs over the first retention blade portion 2053a, and is conveyed to the discharging passage 213 by the second retention blade portion 2053b and is discharged.
Further, regarding the conveying screws 205B and 205C shown in
Further, in the embodiment, a constitution, in which the discharging passage 213 and the discharging portion 208 that discharge the excess developer are arranged in an upstream side of the conveying screw 205 with respect to the developer conveying direction, is described. However, similar to the fifth embodiment, these may be arranged in an upstream side of the mixing chamber 216 with respect to the developer conveying direction. In this case, the developer supply port is arranged, for example, in a downstream side of the developing chamber 215 with respect to the developer conveying direction. Further, similar to the conveying screw 205B shown in
Thus, it is possible to discharge the excess developer from the discharging port 208 and replace the developer automatically. In addition to this, in a case that the mixing screw is driven in a backward direction in the developer discharging mode, it is possible to discharge the developer from the discharging port 208.
In each of the embodiments described above, the supply of the developer to the developing sleeve 203 in the developing chamber 215 as the first chamber and the constitution which collects the developer from the developing sleeve 203 are described. However, the present invention is also possible to apply to a generally known developing device of a function separate type, which supplies the developer to the developing sleeve 203 in the developing chamber 215 as the first chamber and collects the developer from the developing sleeve 203 in the mixing chamber 216 as the second chamber.
Further, the present invention is not limited to a tandem type image forming apparatus 1 using an intermediary transfer method, but may also be an image forming apparatus of other methods. Further, it is not limited to full color, but it may also be monochrome or mono color. Or it may be implemented in various applications such as a printer, various types of printing machines, a copying machine, a fax machine, a multifunction machine, etc.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2021-064900 filed on Apr. 6, 2021, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2021-064900 | Apr 2021 | JP | national |
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